Underwater archaeology is the study of past cultures through artifacts now submerged. Why study humans underwater? These sites often have exemplary preservation or tell unique stories. Whether it is a preserved 10,000 year old brain from a Florida spring or reconstructing life on board a Bronze Age ship, underwater archaeology gives new perspectives on the past.

Archaeology begins right on the shore. We often find things in the intertidal zone- the area between land and sea. This is humans’ first point of contact with water, so it makes sense that things from everyday life are found there- evidence of fishing, boat repair, and buildings that became submerged. Cities sink through processes such as earthquakes, liquefaction, sediment compression, and isostatic sea level change. While at times these processes can appear dramatic the shift is often incremental, meaning that nearly all sunken cities are in shallow depths.

Also in shallow waters, but extending deeper, we find evidence of commerce. These can be shipwrecks, but also abandoned ships that had long, successful careers and were then discarded in old age. In fact, very few ships ever wreck; most are abandoned in shipbreaking yards or ship graveyards. Sometimes old ships are sunk on purpose as a barrier against invaders or to create a pier or breakwater. In these relatively shallow waters we also find evidence of anchorages and harbors, where we see anchors and objects such as broken pots or trash discarded by passing ships. 

Shipwrecks are found at every depth, sunk by crashing into land or other ships, warfare such as the Mars, or in storms such as the USS Monitor. However, the deeper we go the more likely it is that shipwrecks are well preserved. Much of the most important information learned about the past was made possible by finding untouched shipwrecks. 

The greatest difficulty facing underwater archaeology is not accessing sites, but the destruction of sites from looting and treasure hunting. The impact of treasure hunting and collectors is greatly diminishing our ability to understand the past as artifacts disappear at a rapid rate. Archaeological sites are non-renewable resources - once gone, they are gone forever. Pioneer archaeologist Peter Throckmorton wrote that “the Dramont wreck was dynamited by skin divers in 1957. A whole chapter in the history of navigation was blown to rubble by some mindless diver, perhaps hunting for nonexistent gold, destroying not from malice but stupidity, like a bored child spilling the sugar on a rainy afternoon. The glory of the world must indeed pass away, but it seems wrong to speed its passage with dynamite and sledgehammers.” 

Sadly, destruction of sites for treasure have accelerated, despite the fact that few shipwrecks have anything of value outside of their scientific value- as the previous sections examined, most ships are abandoned workboats, not treasure galleons. On land, natural places are conserved with the slogan “Take nothing but photos and leaving nothing but footprints.” However, the sea is not treated with the same respect. In order to save our past we need to think, “taking nothing but photos and leaving nothing but bubbles.” Find out more about protecting underwater sites from UNESCO. 

While this lesson discusses the sea, similar sites and objects are found in rivers, lakes, and underwater caves. The Great Lakes in North America have some of the best preserved shipwrecks (see the Thunder Bay National Marine Sanctuary. Rivers often have beautifully preserved artifacts due to their freshwater. Underwater caves are special sites where can find early human remains, such as Hoyo Negro or evidence of ancient religion such as Cosquer Cave. 

Paleolandscapes are ancient (i.e. paleo) landscapes that were once dry, but have become submerged due to sea level changes. The sea level has change drastically in the time that humans have been around, rising considerably until about 5,000 years ago. Since anatomical modern humans have existed for approximately 150,000 years, the areas of the seafloor that were once dry extend from the current surface to around 200 feet deep. We find everyday parts of life in paleolandscapes, from the shallow footprints at Happisburgh to mammoth skeletons in the North Sea to caribou hunting traps in the Great Lakes.

Deeper than 200 feet we only find objects that have floated down from above, since these areas have always been submerged during human history. These are ships that sank in the deep waters or aircraft that crashed. The Titanic is the most famous deep water wreck. 

Want to learn more about underwater archaeology? Check out the free online course Shipwrecks and Submerged Worlds by the Centre for Maritime Archaeology at the University of Southampton. For general information visit MaritimeArchaeology.com. Find out about the author’s latest discoveries at his website.

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